Quick answer
A pentagon is a polygon with 5 sides.
- Main formula
- Regular perimeter = 5 x side; regular area = (perimeter x apothem)/2.
- Quick example
- If each side measures 4, the perimeter is 20.
Definition
A pentagon is a closed polygon formed by 5 line segments.
Regular pentagon
In a regular pentagon, all sides and all interior angles are equal.
Formulas
- Perimeter of a regular pentagon: P = 5s.
- Area of a regular pentagon: A = (P x a)/2, where a is the apothem.
Example
If a regular pentagon has side length 4, then P = 5 x 4 = 20.